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https://issues.apache.org/jira/browse/HDFS-8574?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14588457#comment-14588457
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Arpit Agarwal commented on HDFS-8574:
-------------------------------------
Hi [~ajithshetty], I don't expect this limit to be hit for a single drive in a
real deployment soon given the NN scalability limits and typical disk sizes.
Splitting based on storage directories was easier to implement and will handles
the block report size issue.
If you just want to test NN namespace/block space limits you can create
multiple storage directories on a single volume. The free space calculations
will be off but that won't matter for your test. If you feel strongly about
splitting reports for a single storage we can keep this Jira around.
Also the message is likely due to hitting the default protobuf message size
limit of 64MB which is hit around 9-10M blocks.
> When block count for a volume exceeds dfs.blockreport.split.threshold, block
> report causes exception
> ----------------------------------------------------------------------------------------------------
>
> Key: HDFS-8574
> URL: https://issues.apache.org/jira/browse/HDFS-8574
> Project: Hadoop HDFS
> Issue Type: Bug
> Affects Versions: 2.7.0
> Reporter: Ajith S
> Assignee: Ajith S
>
> This piece of code in
> {{org.apache.hadoop.hdfs.server.datanode.BPServiceActor.blockReport()}}
> {code}
> // Send one block report per message.
> for (int r = 0; r < reports.length; r++) {
> StorageBlockReport singleReport[] = { reports[r] };
> DatanodeCommand cmd = bpNamenode.blockReport(
> bpRegistration, bpos.getBlockPoolId(), singleReport,
> new BlockReportContext(reports.length, r, reportId));
> numReportsSent++;
> numRPCs++;
> if (cmd != null) {
> cmds.add(cmd);
> }
> {code}
> when a single volume contains many blocks, i.e more than the threshold, it is
> trying to send the entire blockreport in one RPC, causing exception
> {code}
> java.lang.IllegalStateException:
> com.google.protobuf.InvalidProtocolBufferException: Protocol message was too
> large. May be malicious. Use CodedInputStream.setSizeLimit() to increase
> the size limit.
> at
> org.apache.hadoop.hdfs.protocol.BlockListAsLongs$BufferDecoder$1.next(BlockListAsLongs.java:369)
> at
> org.apache.hadoop.hdfs.protocol.BlockListAsLongs$BufferDecoder$1.next(BlockListAsLongs.java:347)
> at
> org.apache.hadoop.hdfs.protocol.BlockListAsLongs$BufferDecoder.getBlockListAsLongs(BlockListAsLongs.java:325)
> at
> org.apache.hadoop.hdfs.protocolPB.DatanodeProtocolClientSideTranslatorPB.blockReport(DatanodeProtocolClientSideTranslatorPB.java:190)
> at
> org.apache.hadoop.hdfs.server.datanode.BPServiceActor.blockReport(BPServiceActor.java:473)
> {code}
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